This invention relates to a field sprayer and more particularly to a shield attachment to the sprayer to improve the spraying action.
Field sprayers have become a very important item of agricultural equipment as the use of agricultural chemicals has increased.
Conventional field sprayers are of the type having an elongate support frame for transport across field transverse to the length of the frame, a liquid supply boom extending longitudinally of the frame and a plurality of nozzles along the length of the boom for spraying the field.
Generally, sprayers of this type have a pair of such booms extending outwardly from a central wheeled truck sections supporting the tanks that supply the liquid to be sprayed. On this framework, 60' to 100' in length, spray booms are supported at one or two positions by ground wheels.
Spray covers are well known and regularly used on agricultural sprayers, however their effectiveness may vary. Sprayers are open to the elements, especially the wind so that spray drift is a problem at all times and at wind velocities greater than very low speeds effectively prevents use of the equipment. A number of spray covers or enclosures have been developed to reduce the wind effect on spray drift during spraying. There are many devices that fully enclose a spraying area from the ground up to and including the sprayer nozzles. Even with such fully enclosed devices, spray drift however is still a problem with many designs of sprayshield. In addition, in view of the expense and complication and the reduced access available with fully enclosed systems, many designs of reduced size of cover have been proposed. These designs are however, in many cases, ineffective and still do not provide access to the enclosed spray nozzles for routine maintenance or repair.
A review of the prior art discloses a number of spray cover devices, all of which claim to minimize wind drift, each with a varying degree of success (U.S. Pat. No. 4,646,971; U.S. Pat. No. 4,641,781 and U.S. Pat. No. 4,272,589). In each case, the spray nozzles are within the device and quick maintenance of, for example a plugged nozzle, is not easily accomplished. Also, since the nozzles are not visible, the operator may continue to spray the field for a long time without realizing that a spray nozzle is faulty thus leading to areas of reduced spray or areas of increased spray, both of which can be equally damaging to the crop.
Modern spray material may be considered a hazzard to people's health and other life forms. It may also be harmful to a crop in excess. If a crop is not sprayed, the crop may also suffer as it will then be susceptible to weed growth or insect attack. A properly operating sprayer is essential to overcome these potential hazzards.
U.S. Pat. No. 4,646,971 (Rogers) discloses an arrangement in which the spray nozzle is mounted exteriorly of the shield but the mouth of the nozzle and the whole of the spray pattern are fully covered by the shield so that the pattern is not visible.
A design by Brandt shown in their brochure entitled Hydraulic Quick-Folding Field Sprayers provides a short length shield known as a "Windlore" (trademark) covering only the nozzle and a part of the pattern. However this has little effect on the drift problem.
A design, by Bourgault shown in their brochure entitled "Air curtain" comprises a device intended to develop a air curtain by jetting air downwardly in front of and behind the pattern.
Flexicoil as shown in their brochure entitled "Sprayer Windscreen" provides a device which has openings through the shield.
None of these devices however allows viewing of and easy access to the nozzle and none utilizes properly air flow around the area of the pattern to properly protect the pattern.